1. Field of the Invention
The present invention relates to a stock preparation system for preparing a fiber suspension for use in a paper-making machine, and, more particularly, to a pulper in such a stock preparation system.
2. Description of the Related Art
A fiber stock preparation system is used to make a fiber suspension from a source of fiber such as wood. The fiber stock preparation system receives the raw source of fiber, breaks the raw source of fiber into individual fibers suspended within a liquid such as water, and separates contaminants from the fiber suspension.
It is known to provide a pulper in a fiber stock preparation system as described above to break down the raw source of fiber into individual fibers. A pulper typically includes a rotatable element therein which imparts mechanical forces to the source of fiber and breaks the source of fiber into individual fibers. The pulped fiber is transported downstream to other mechanical devices within the stock preparation system. For example, the pulped fiber may be further processed within a disperger. A disperger receives the pulped fiber, removes contaminants from the fiber suspension and thoroughly mixes chemicals within the fiber suspension. The disperger includes a shaft assembly with a plurality of foils which move in very close proximity relative to a plurality of foils carried by a housing. The tight tolerances within the disperger are intended to process the liquid under relatively high pressure so that the chemicals may be thoroughly mixed and the contaminants removed. To achieve thorough mixing of the chemicals, the dwell time of the fiber suspension within the disperger is relatively long. The disperger has an output which is in the form of an open end of the housing which discharges directly to the ambient environment. Because of the tight tolerances and pressures utilized within the disperger, the consistency of the input source of fiber must be relatively low in order for the disperger to operate properly without clogging. That is, the input source of fiber must have a high percentage of water by weight in order for the disperger to operate properly. For this and other reasons, such a disperger has a low throughput rate.
What is needed in the art is a pulper which can pulp an input source of fiber with a relatively high input consistency, and at a high throughput rate.
The present invention provides a pulper in a stock preparation system with a plurality of individually controllable augers which extend into an inner chamber of a housing.
The invention comprises, in one form thereof, a pulper in a stock preparation system. The pulper includes a housing with a fiber inlet, at least one water inlet, at least one outlet and an inner chamber. A plurality of rotatable augers extend into the inner chamber.
An advantage of the present invention is that a pulper with a simplified construction and high throughput rate is provided.
Another advantage is that the pulper is capable of pulping an input source of fiber that has a relatively high consistency.
Yet another advantage is that each of the augers is individually controllable and reversible, thereby avoiding clogs and maximizing both the throughput rate and the consistency of input fiber that can be pulped.
A further advantage is that the pulper is capable of pulping larger pieces of an input source of fiber. Thus, no shredder is required for shredding bales of wastepaper.